Sarani Zakaria

Citric acid modified kenaf core fibres for removal of methylene blue from aqueous solution.

Chemically modified kenaf core fibres were prepared via esterification in the presence of citric acid (CA). The adsorption kinetics and isotherm studies were carried out under different conditions to examine the adsorption efficiency of CA-treated kenaf core fibres towards methylene blue (MB). The adsorption capacity of the kenaf core fibres increased significantly after the citric acid treatment. The values of the correlation coefficients indicated that the Langmuir isotherm fitted the experimental data better than the Freundlich isotherm. The maximum adsorption capacity of the CA-treated kenaf core fibres was found to be 131.6mg/g at 60°C. Kinetic models, pseudo-first-order, pseudo-second-order and intraparticle diffusion, were employed to describe the adsorption mechanism. The kinetic data were found to fit pseudo-second-order model equation as compared to pseudo-first-order model. The adsorption of MB onto the CA-treated kenaf core fibres was spontaneous and endothermic.

Cationic and anionic modifications of oil palm empty fruit bunch fibers for the removal of dyes from aqueous solutions

Oil palm empty fruit bunch (EFB) fibers were employed to remove dyes from aqueous solutions via adsorption approaches. The EFB fibers were modified using citric acid (CA) and polyethylenimine (PEI) to produce anionic and cationic adsorbents, respectively. The CA modified EFB fibers (CA-EFB) and PEI-modified EFB fibers (PEI-EFB) were used to study the efficiency in removing cationic methylene blue (MB) and anionic phenol red (PR) from aqueous solutions, respectively, at different pHs, temperatures and initial dye concentrations. The adsorption data for MB on the CA-EFB fitted the Langmuir isotherm, while the adsorption of PR on the PEI-EFB fitted the Freundlich isotherm, suggesting a monolayer and heterogeneous adsorption behavior of the adsorption processes, respectively. Both modified fibers can be regenerated up to seven adsorption/desorption cycles while still providing as least 70% of the initial adsorption capacity.

Comparative studies of products obtained from solvolysis liquefaction of oil palm empty fruit bunch fibres using different solvents

Solvolysis of oil palm empty fruit bunches (EFB) fibres using different solvents (acetone, ethylene glycol (EG), ethanol, water and toluene) were carried out using an autoclave at 275°C for 60 min. The solvent efficiency in term of conversion yield was found to be: EG>water>ethanol>acetone>toluene. The liquid products and residue obtained were analyzed using Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass selectivity. The obtained results showed that the chemical properties of the oil product were significantly affected by the type of solvent used for the solvolysis process. The higher heating value (HHV) of oil products obtained using ethanol is ∼29.42 MJ/kg, which is the highest among the oil products produced using different solvents. Water, ethanol and toluene yield major phenolic compounds. While EG favors the formation of alcohol compounds and acetone yields ketone and aldehyde compounds.

Antibacterial performance of Ag nanoparticles and AgGO nanocomposites prepared via rapid microwave-assisted synthesis method

Silver nanoparticles and silver-graphene oxide nanocomposites were fabricated using a rapid and green microwave irradiation synthesis method. Silver nanoparticles with narrow size distribution were formed under microwave irradiation for both samples. The silver nanoparticles were distributed randomly on the surface of graphene oxide. The Fourier transform infrared and thermogravimetry analysis results showed that the graphene oxide for the AgNP-graphene oxide (AgGO) sample was partially reduced during the in situ synthesis of silver nanoparticles. Both silver nanoparticles and AgGO nanocomposites exhibited stronger antibacterial properties against Gram-negative bacteria (Salmonella typhi and Escherichia coli) than against Gram-positive bacteria (Staphyloccocus aureus and Staphyloccocus epidermidis). The AgGO nanocomposites consisting of approximately 40 wt.% silver can achieve antibacterial performance comparable to that of neat silver nanoparticles.

Direct production of biodiesel from high-acid value Jatropha oil with solid acid catalyst derived from lignin

BackgroundSolid acid catalyst was prepared from Kraft lignin by chemical activation with phosphoric acid, pyrolysis and sulfuric acid. This catalyst had high acid density as characterized by scanning electron microscope (SEM), energy-dispersive x-ray spectrometry (EDX) and Brunauer, Emmett, and Teller (BET) method analyses. It was further used to catalyze the esterification of oleic acid and one-step conversion of non-pretreated Jatropha oil to biodiesel. The effects of catalyst loading, reaction temperature and oil-to-methanol molar ratio, on the catalytic activity of the esterification were investigated.ResultsThe highest catalytic activity was achieved with a 96.1% esterification rate, and the catalyst can be reused three times with little deactivation under optimized conditions. Biodiesel production from Jatropha oil was studied under such conditions. It was found that 96.3% biodiesel yield from non-pretreated Jatropha oil with high-acid value (12.7 mg KOH/g) could be achieved.ConclusionsThe catalyst can be easily separated for reuse. This single-step process could be a potential route for biodiesel production from high-acid value oil by simplifying the procedure and reducing costs.

Cellulose nanofibrils: a rapid adsorbent for the removal of methylene blue

Cellulose nanofibrils (CNF) were prepared from kenaf core (KC) using acidified-chlorite bleaching method and followed by disintegration using a high speed blender. The effects of disintegration time and acid treatment on the defibrillation of holocellulose were studied. Hemicellulose was found to facilitate defibrillation, as CNF without any acid treatment was fully defibrillated after 30 min. The adsorption kinetics of CNF toward cationic dye cannot be accurately determined due to its quick adsorption performance, in which the equilibrium is achieved immediately after 1 min of contact time. The effects of acid treatment on holocellulose, pH, adsorbent dosage, temperature and dye concentration were studied and optimized. Adsorption data were fitted to both Langmuir and Freundlich models where the Langmuir model was found to be the better model to describe the adsorption process. The maximum adsorption capacity was found to be 122.2 mg g−1 at pH 9, 20 °C for the non-acid treated CNF. The CNF can be regenerated by desorption at low pH where as much as 70% of the dye adsorbed can be desorbed after 6 cycles of adsorption–desorption.

Bifunctional graphene oxide–cellulose nanofibril aerogel loaded with Fe(III) for the removal of cationic dye via simultaneous adsorption and Fenton oxidation

A highly porous cellulose nanofibril (CNF) aerogel loaded with graphene oxide–iron(III) (GO–Fe) nanocomposites was produced and used for the treatment of methylene blue (MB) in aqueous solution. The CNF aerogel serves as an adsorbent for the dye, while the GO–Fe nanocomposites play a role in the decomposition of the dye via the Fenton oxidation reaction. The aerogel exhibits rapid adsorption performance (less than 10 min) for removing MB, with a maximum adsorption capacity of 142.3 mg g−1. On the side of enhancing the MB removal, the GO in the GO–CNF nanocomposite aerogel was loaded with 1 wt% of Fe(III) to perform as a catalyst for the Fenton oxidation reaction. The MB continues to decolorize by 30.4% more after 24 h of the reaction process. Moreover, by performing Fenton oxidation for adsorbent regeneration, the adsorption capacity for nanocomposite adsorption was reduced by 52.2% after five cycles of adsorption–oxidation.

High yield production of sugars from deproteinated palm kernel cake under microwave irradiation via dilute sulfuric acid hydrolysis

Recent years, great interest has been devoted to the conversion of biomass-derived carbohydrate into sugars, such as glucose, mannose and fructose. These are important versatile intermediate products that are easily processed into high value-added biofuels. In this work, microwave-assisted dilute sulfuric acid hydrolysis of deproteinated palm kernel cake (DPKC) was systematically studied using Response Surface Methodology. The highest mannose yield (92.11%) was achieved at the optimized condition of 148°C, 0.75N H2SO4, 10min 31s and substrate to solvent (SS) ratio (w/v) of 1:49.69. Besides that, total fermentable sugars yield (77.11%), was obtained at 170°C, 0.181N H2SO4, 6min 6s and SS ratio (w/v) of 1:40. Ridge analysis was employed to further verify the optimum conditions. Thus, this work provides fundamental data of the practical use of DPKC as low cost, high yield and environmental-friendly material for the production of mannose and other sugars.

Mechanical Properties of Kenaf–Thermoplastic Natural Rubber Composites

Kenaf–thermoplastic natural rubber (Kenaf–TPNR) composites were developed and evaluated in this study. The kenaf was blended with TPNR and maleic anhydride-grafted polypropylene (MAPP) as a compatibilizer in an internal mixer (Brabender). The mechanical properties of the composites were investigated by tensile, impact, flexural, and morphologic properties by scanning electron microscope (SEM). The incorporation of the kenaf fiber into the TPNR matrix resulted in an improvement in the tensile strength and Youngs modulus. However, the maximum strain and impact strength decreased with increased filler loading. The better performance was attributed to the addition of MAPP due to improvements in the wetting of the filler surface. The addition of MAPP produced composites with improved tensile strength, Youngs modulus, and flexural stiffness. SEM was employed to investigate the fiber surface, fiber pullout, and fiber–matrix interaction of composites.

POLYSTYRENE-BENZOYLATED EFB REINFORCED COMPOSITES

Reinforced thermoplastics generally are produced by incorporation of reinforcement agents or fillers into thermoplastic resins. The utilization of lignocellulosic material as filler with reinforcement in polymer matrix has received much interest due to its lower price and other properties. A composite of polystyrene reinforced with oil palm empty fruit bunches (EFB) and chemically treated EFB with benzoyl chloride (EFB-benzoylated) as a function of loading and fiber surface modification were prepared. The chemically treated fibers were analyzed with FT-IR to observe the extent of chemical reaction with EFB fiber. The sharp peak at 710 cm−1 appeared on the spectra, which indicated that the mono-substituted benzene ring has taken place. The strong peak at 1720 cm−1 has indicated the presence of ester group treated fiber. The flexural test was performed using Instron 4301 testing machine to study flexural properties of the composites with various fiber sizes. The results showed that the flexural properties increased with particle size. The flexural strength of EFB-benzoylated composites was observed to be stronger than untreated EFB fiber. Scanning electron microscope was used to investigate the morphological structure of the fiber surface, fiber pull out, fracture surface, and fiber–matrix interface. The untreated EFB composites showed hole and fiber end, which indicated that most of the fiber have pulled out breaking during the fracture of composites; however, the treated EFB-benzoylated showed a good adhesion between fiber and matrix.